Heat exchanger apparatus with integrated supply/return tube

ABSTRACT

A heat exchanger apparatus includes a first and second coolant tanks spaced apart from each other, a plurality of heat exchanging tubes extending between the tanks for enabling coolant to flow from the first coolant tank to the second coolant tank and to be cooled in said tubes, and a coolant supply/return tube for enabling coolant to flow from the second coolant tank to the first coolant tank. The supply/return tube has a substantially circular cross-section. The supply/return tube has opposite end portions inserted into complementary openings in the inlet coolant reservoir and the first tank. In order to provide the proper, predetermined orientation of the supply/return tube in the heat exchanger apparatus, the supply/return tube has opposite locating members each adjacent to the end portions of the supply/return tube, so that a small, predetermined length of the end portions of the supply/return tube protrudes inside the supply/return tube.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to heat exchangers, and moreparticularly to a heat exchanger apparatus having integrated fluidsupply/return tube.

[0003] 2. Description of the Prior Art

[0004] In a conventional brazed aluminum single-pass compact heatexchanger, where the internal working fluid makes only one pass throughthe heat exchanger, the inlet and outlet ports are located on theopposite ends of the heat exchanger. In such single-pass heatexchangers, if the inlet and outlet ports are required to be on the sameside of the heat exchanger (due to space, manufacturing or otherconstraints), then an additional supply/return tube is used to transportthe fluid from one end to the other. This additional tube to transportthe working fluid from one end to the other end of the heat exchangercould either be external to the heat exchanger (in which case, this tubeis assembled to the heat exchanger in a secondary manufacturingoperation after the heat exchanger is manufactured) or could be internalto the heat exchanger (in which case this tube is assembled to theexchanger prior to the brazing process). In the latter case, the tube issaid to be integrated into the heat exchanger.

[0005] Using the external tube to transport the fluid from one end ofthe heat exchanger to the other poses various problems as describedbelow:

[0006] 1. Since the supply/return tube is external to the heatexchanger, the tube needs to be supported and secured to the heatexchanger by means of additional clips, brackets and/or fasteners. Thesebrackets, fasteners, etc. add piece cost and additional manufacturingand assembly costs.

[0007] 2. Since this tube is not part of the heat exchanger, one or moreadditional connection joints are required where the tube interfaces withthe internal portion of the heat exchanger. Since these systemstypically operate at relatively high internal pressures, theseconnections have to be designed to withstand these higher operatingpressures. Typically connection designs include o-ring fittings, flarefittings, threaded fittings with thread sealants, etc. Such connectionscould become expensive. Further, every additional connection is apotential leak path and a potential failure spot.

[0008] 3. External tubes require additional manufacturing and assemblyoperations to assemble them to the heat exchanger. Further, anyadditional requirements like painting or corrosion protection coatingsapplied to the heat exchanger would be required for this external tubealso. All these would make the assembly significantly more expensive.

[0009] 4. Typically, most such systems require the internal fluid-sidepressure drop to be kept to a minimum. Adding additional connections tothe heat exchanger increases internal pressure drop significantly (dueto entrance and exit losses, losses due to reduced cross sectional flowareas and due to the flow directional changes). In applications such asautomotive transmission oil cooling and engine oil cooling, the oilpumps have very low output power. A high internal pressure drop in theheat exchanger, in such applications could lead to no oil flow throughthe exchanger and consequently a complete system failure.

[0010] 5. Since the tube is external with added brackets, clips,fasteners, etc., the part is more complex and hence, more prone to fieldfailures, i.e., they are more likely to be less durable than anintegrated tube design.

[0011] 6. Since the tube is not part of the heat exchanger, additionalspace is required to package it properly. In automotive application, forexample, packaging constraints can be very tight, therefore anintegrated tube design is likely easier to be packaged.

[0012] Thus, there is a need for a heat exchange apparatus that issimple and inexpensive to manufacture, and allows to withstandsubstantial internal pressure of the coolant flow without reinforcingthe supply/return tube walls.

SUMMARY OF THE INVENTION

[0013] The present invention provides a novel arrangement of a heatexchanger apparatus having an integrated supply/return tube. The heatexchanger apparatus of the present invention comprises a first tank, asecond tank and a heat exchanger core extending between the first tankand the second tank. The second tank is in turn divided into twohermetically separated reservoirs: a cooling reservoir and asupply/return reservoir, by a partition wall. The cooling reservoir isprovided with an outlet port, while the supply/return reservoir isprovided with an inlet port. The heat exchanger core comprises aplurality of heat transfer tubes spaced from each other in asubstantially parallel arrangement, and a supply/return tubesubstantially parallel to the heat transfer tubes. Preferably, thesupply/return tube has substantially circular cross-section, and is madeof aluminum alloy. Furthermore, the supply/return tube is provided withopposite locating members integrally formed at the opposite end portionsthereof in order to provide the proper, predetermined orientation of thesupply/return tube in the heat exchanger apparatus. The supply/returntube extends for a small, pre-determined length past the locatingmembers on the two opposite ends thereof. The position of these locatingmembers determines the exact penetration of the supply/return tube intothe first and second tanks.

[0014] The supply/return tube is mechanically assembled to the heatexchanger, then brazed to the heat exchanger, thus becoming an integralpart of the heat exchanger.

[0015] When assembled, the supply/return tube firmly contacts adjacentfin on the heat exchanger, the end portions of the supply/return tube(past the locating members) penetrate into mating holes in the two tanksand the locating members make a positive contact with the tanks. Besidescontrolling the exact penetration depth of the tube extension into thetank, the locating member also makes a firm surface contact with thetank for obtaining good brazing and hence good joint integrity andquality.

[0016] In accordance with the first exemplary embodiment of the presentinvention, the first and second tanks have a generally rectangularcross-section, and the locating members are in the form of annularflanges integrally formed at the opposite ends of the supply/returntube.

[0017] In accordance with the second exemplary embodiment of the presentinvention, the first and second tanks have a generally circularcross-section, and the locating members are in the form of substantiallysemi-cylindrical flanges integrally formed at the opposite end portionsof the supply/return tube.

[0018] In accordance with the third exemplary embodiment of the presentinvention, the locating members are in the form of seat members eachjuxtaposed to the end portions of the supply/return tube. The seatmembers are formed by providing the end portions of the supply/returntube of reduced diameter as compared to a central portion thereof.

[0019] Therefore, the heat exchanger apparatus in accordance with thepresent invention represents a novel arrangement that is simple andinexpensive in manufacturing, easy to assemble, and allows to withstandsubstantial internal pressure of the coolant flow without reinforcingthe supply/return tube walls.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other objects and advantages of the invention will becomeapparent from a study of the following specification when viewed inlight of the accompanying drawings, wherein:

[0021]FIG. 1 is a partial sectional view of a heat exchanger apparatusin accordance with the first exemplary embodiment of the presentinvention;

[0022]FIG. 2 is a partial view of a supply/return tube in accordancewith the first embodiment of the present invention;

[0023]FIG. 3 is a partial perspective view of the heat exchangerapparatus in accordance with the second exemplary embodiment of thepresent invention;

[0024]FIG. 4 is a partial view of a supply/return tube in accordancewith the second embodiment of the present invention;

[0025]FIG. 5 is a partial sectional view of a connection between thesupply/return tube and a first tank in the heat exchanger apparatus inaccordance with the second exemplary embodiment of the presentinvention;

[0026]FIG. 6 is a partial view of a supply/return tube in accordancewith the third exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] The preferred embodiments of the present invention will now bedescribed with the reference to accompanying drawings.

[0028]FIG. 1 of the drawings illustrates the first exemplary embodimentof a heat exchanger apparatus in accordance with the present invention,generally indicated at 1, in accordance with the present invention. Theheat exchanger apparatus 1 comprises a first tank 2, a second tank 4 anda heat exchanger core 6 extending between the first tank 2 and thesecond tank 4. The second tank 4 is divided into two hermeticallyseparated reservoirs: an outlet coolant reservoir 8 and an inlet coolantreservoir 10, by a partition wall 12. The outlet coolant reservoir 8 isprovided with an outlet port 9, while the inlet coolant reservoir 10 isprovided with an inlet port 11. Coolant, used with the heat exchangerapparatus of the present invention, may be oil, antifreeze, or any otherappropriate coolant fluid, well known to those skilled in the art.

[0029] The heat exchanger core 6 comprises a plurality of heat transfertubes 14 spaced from each other in a substantially parallel arrangement.Typically, the heat transfer tubes 14 have non-circular configuration,such as oval or rectangular. Between each two adjacent heat transfertubes 14 there are fins 15 of corrugated sheet metal. The heat transfertubes 14 fluidly interconnect the first tank 2 with the outlet coolantreservoir 8 of the second tank 4 in order to enable coolant to flow fromthe first tank 2 to the outlet coolant reservoir 8 and to be cooled insaid tubes. Furthermore, the heat exchanger core 6 comprises asupply/return tube 16 spaced from the heat transfer tubes 14. Thesupply/return tube 16 fluidly interconnects the first tank 2 with theinlet coolant reservoir 10 of the second tank 4 in order to enablecoolant to flow from the inlet coolant reservoir 10 to the first tank 2.It will be appreciated that the heat exchanger core 6 in accordance withthe present invention may include more than one supply/return tube 16,such as two, three, etc. In accordance with the preferred embodiment ofthe present invention, the supply/return tube 16 has substantiallycircular cross-section. The circular supply/return tube would be astandard commercial tube requiring no special tooling or process tomanufacture. The circular tube generally offers increased flow crosssectional areas. Thus, the internal pressure reduces significantly.Moreover, since a circular cross section has the bestpressure-containing characteristic, reduction in tube wall thickness ispossible. This significantly simplifies manufacturing process, reducescost, and allows to withstand substantial internal pressure of thecoolant flow without reinforcing the tube walls. Preferably, thesupply/return tube 16 is made of aluminum or aluminum alloy. However,other shapes of the supply/return tube 16 and materials it is made of,are also within the scope of the present invention.

[0030] Moreover, the supply/return tube 16 has opposite end portions 16′and 16″ inserted into complementary openings in the inlet coolantreservoir 10 and in the first tank 2, respectively. More specifically,an inner wall 3 of the first tank 2 is provided with an openingreceiving the end portions 16′ of the supply/return tube 16.Correspondingly, an inner wall 5 of the second tank 4 is provided withan opening receiving the end portions 16″ of the supply/return tube 16.

[0031] In order to provide the proper, predetermined orientation of thesupply/return tube 16 in the heat exchanger apparatus 1, thesupply/return tube 16 has opposite locating members each adjacent to theend portions of the supply/return tube 16, so that a small,predetermined length d of the end portions 16′ and 16″ of thesupply/return tube 16 is provided between the locating member and endfaces 17 of the supply/return tube 16. Thus, the position of thelocating members on the supply/return tube 16 determines the exactpenetration of the supply/return tube 16 into the first tank 2 and theinlet reservoir 10 of the second tank 4. Hence, the length of thesupply/return tube 16 penetrating into the tanks 2 and 4 can bemaintained as short as required. This completely eliminates the flowblockage where the supply/return tube penetrates into the tanks, thusresulting in a significant internal pressure drop reduction.

[0032] Furthermore, the locating members aid the supply/return tube 16firmly seat on a surface of the tank. Thus, an excellent braze jointcould be obtained.

[0033] In the first exemplary embodiment of the present invention,illustrated in FIGS. 1 and 2, the first and second tanks 2 and 4 have agenerally rectangular cross-section, and the locating members are in theform of annular flanges 18′ and 18″ each integrally formed at theopposite ends of the supply/return tube 16. As shown in FIG. 1, theannular flange 18′ of the supply/return tube 16 firmly contacts a flatinner wall 3 of the first tank 2 and is secured thereto by brazing.Similarly, the other annular flange 18″ of the supply/return tube 16firmly contacts a flat inner wall 5 of the second tank 4 and is securedthereto by brazing. Thus, the annular flanges 18′ and 18″ allowcontrolling the depth of penetration of the end portions 16′ and 16″ ofthe supply/return tube 16 into the first tank 2 and the inlet reservoir10 of the second tank 4, respectively. Moreover, the annular flanges 18′and 18″ provide firm contact between the supply/return tube 16 and thefirst and second tanks 2 and 4, thus ensuring strength and integrity ofthe heat exchanger apparatus 1.

[0034] In operation, coolant enters the inlet reservoir 10 of the secondtank 4 through the inlet port 11, then flows to the first tank 2 via thesupply/return tube 16. It then flows in the opposite direction to theoutlet reservoir 8 of the second tank 4 through the plurality of theheat transfer tubes 14. Coolant leaves the heat exchanger apparatus 1through the outlet port 9. It will be appreciated that the heat exchangeapparatus of the present invention wherein the coolant flows in theopposite direction, e.g. from the outlet reservoir 8 through the heattransfer tubes 14 to the first tank 2, then back to the inlet reservoir10 through the supply/return tube 16, is within the scope of the presentinvention.

[0035] FIGS. 3-5 of the drawings illustrate the second exemplaryembodiment of a heat exchanger apparatus. Components, which areunchanged from, or function in the same way as in the first exemplaryembodiment depicted in FIGS. 1-2 are labeled with the same referencenumerals, sometimes without describing detail since similarities betweenthe corresponding parts in the two embodiments will be readily perceivedby the reader.

[0036] In the heat exchanger apparatus 100 of the second exemplaryembodiment of the present invention, as illustrated in FIGS. 3 and 5,includes a first tank and a second tank (only the first tank 102 isshown in the accompanying drawings) which have a generally circularcross-section. A substantially cylindrical supply/return tube 116fluidly interconnects the first and second tanks. The supply/return tube116 has opposite end portions 116′ and 116″ inserted into complementaryopenings in an inlet coolant reservoir of the second tank (not shown)and into the first tank 102, respectively. In order to provide theproper, predetermined orientation of the supply/return tube 116 in theheat exchanger apparatus 100, the supply/return tube 116 has oppositelocating members each adjacent to the end portions 116′ and 116″ of thesupply/return tube 116.

[0037] In accordance with the second exemplary embodiment of the presentinvention, the locating members are in the form of substantiallysemi-cylindrical flanges 118 each integrally formed at the opposite ends116′ and 116″ of the supply/return tube 116. The semi-cylindricalflanges 118 of the supply/return tube 116 firmly contact outer walls ofthe cylindrical first tank 102 (as shown in FIG. 5) and the second tank,respectively, and are secured thereto by brazing. Thus, the flanges 118allow controlling the depth of penetration of the end portions 116′ and116″ of the supply/return tube 116 into the first tank 102 and the inletreservoir of the second tank, respectively. Moreover, the flanges 118provide firm contact between the supply/return tube 116 and the firstand second tanks, thus ensuring strength and integrity of the heatexchanger apparatus 100.

[0038] In the third exemplary embodiment of a supply/return tube 216 inaccordance with the present invention, illustrated in FIG. 6, thelocating members are in the form of seat members 218 (only one is shown)each juxtaposed to the end portions 216′ of the supply/return tube 216opposite to the end face 217 thereof. More specifically, the seatmembers 218 are formed by providing the end portions 216′ of thesupply/return tube 216 of reduced diameter as compared to a centralportion 219 thereof. Correspondingly, the openings in a first tank (notshown) and an inlet coolant reservoir (not shown) are adapted to receivethe end portions 216′ and 216″ of the supply/return tube 216 only, asthey are of substantially smaller diameter than the central portion 219thereof. Thus, the seat members 218 allow controlling the depth ofpenetration of the end portions 216′ of the supply/return tube 216 intothe first tank and the inlet reservoir of the second tank, respectively.Moreover, the seat members 218 provide firm contact between thesupply/return tube 216 and the first and second tanks, thus ensuringstrength and integrity of the heat exchanger apparatus 1.

[0039] Therefore, the heat exchanger apparatus in accordance with thepresent invention represents a novel arrangement that is simple andinexpensive in manufacturing, easy to assemble, and allows to withstandsubstantial internal pressure of the coolant flow without reinforcingthe supply/return tube walls. The heat exchanger apparatus of thepresent invention provides the following advantages over the heatexchangers of the prior art having external supply/return tubes:

[0040] 1. The supply/return tube is integrated into the heat exchangerand is one-shot brazed. This leads to the elimination of severalsecondary manufacturing operations.

[0041] 2. The integrated supply/return tube results in a significantreduction of components (fittings for the external tube, clips,brackets, fasteners required to secure the external tube to the heatexchanger, etc.).

[0042] 3. Reduction in design complexity and hence, cost (externalsupply/return tube with fittings is very expensive compared to theproposed integrated supply/return tube solution).

[0043] 4. Elimination of additional connections and joints. This leadsto a reduction in the potential leak paths and failure spots.

[0044] 5. A significantly more compact design: integration of thesupply/return tube into the heat exchanger leads to a significantreduction in the physical size.

[0045] 6. Significantly improved product durability compared to anexternal supply/return tube design.

[0046] 7. If any painting or corrosion protection coating is required,it could be applied all at once along with the heat exchanger. Thisleads to significant cost reductions.

[0047] The foregoing description of the preferred embodiments of thepresent invention has been presented for the purpose of illustration inaccordance with the provisions of the Patent Statutes. It is notintended to be exhaustive or to limit the invention to the precise formsdisclosed. The embodiments disclosed hereinabove were chosen in order tobest illustrate the principles of the present invention and itspractical application to thereby enable those of ordinary skill in theart to best utilize the invention in various embodiments and withvarious modifications as are suited to the particular use contemplated,as long as the principles described herein are followed. Thisapplication is therefore intended to cover any variations, uses, oradaptations of the invention using its general principles. Further, thisapplication is intended to cover such departures from the presentdisclosure as come within known or customary practice in the art towhich this invention pertains. Thus, changes can be made in theabove-described invention without departing from the intent and scopethereof. It is also intended that the scope of the present invention bedefined by the claims appended thereto.

What is claimed is:
 1. A heat exchanger apparatus comprising: a firstcoolant tank; a second coolant tank spaced apart from said first coolanttank, said second tank includes an inlet reservoir and an outletreservoir; and a heat exchanger core extending between said tanks, saidheat exchanger core including: a plurality of heat exchanging tubesfluidly interconnecting said first coolant tank and said outletreservoir of said second coolant tank for cooling a coolant in saidtubes; and at least one coolant supply/return tube for fluidlyinterconnecting said inlet reservoir of said second coolant tank andsaid first coolant tank and for enabling coolant to flow between saidcoolant tanks in the direction opposite to flow of said coolant in saidheat exchanging tubes.
 2. The heat exchanger apparatus as defined inclaim 1, wherein said inlet reservoir includes an inlet port, and saidoutlet reservoir includes an outlet port.
 3. The heat exchangerapparatus as defined in claim 1, wherein said supply/return tube hassubstantially circular cross-section.
 4. The heat exchanger apparatus asdefined in claim 3, wherein each of said heat exchanging tubes hassubstantially non-circular cross-section.
 5. The heat exchangerapparatus as defined in claim 1, wherein said supply/return tube haslocating members each provided adjacent to opposite end portions of saidsupply/return tube so that a predetermined length of one of said endportions of said supply/return tube extends within said first tank and apredetermined length of another of said end portions of saidsupply/return tube extends within said inlet reservoir of said secondtank.
 6. The heat exchanger apparatus as defined in claim 5, whereinsaid locating members are in the form of substantially annular flangesintegrally formed on said supply/return tube.
 7. The heat exchangerapparatus as defined in claim 5, wherein said locating members are inthe form of substantially semi-cylindrical flanges integrally formed onsaid supply/return tube.
 8. The heat exchanger apparatus as defined inclaim 7, wherein each said first coolant tank and said second coolanttank has substantially circular cross-section complementary to saidsemi-cylindrical flanges of said supply/return tube.
 9. The heatexchanger apparatus as defined in claim 5, wherein each of said locatingmembers is in the form of a seat member formed by reducing diameter ofsaid end portion of said supply/return tube relative to a centralportion thereof.
 10. The heat exchanger apparatus as defined in claim 1,wherein said supply/return tube is made of aluminum.
 11. The heatexchanger apparatus as defined in claim 1, wherein said supply/returntube is secured to said coolant tanks by brazing.